Tell her how you feel, respectfully and tactfully, honest communication is they key.
And in regards to that picture...
Dear god why do you allow so much violence on the streets and in peoples homes because you are allowed in those.
What a load of nonsense mumbo jumbo and some more swearing words

This is, I think, the time to honestly, but considerately, 'put your cards on the table'.

Let her know you're an atheist. Let her know that she has every right to her beliefs - but if she were to try and 'impose' them on you, or on others in your presence, that would be an issue ... and see how she reacts.

This is the main reason i am careful to not mix the Internet with real life. People are two different personalities on Facebook v. real life. In my experience, both personalities are the real person.

Just tell her you've had a change of plans. Which is true.
If she presses, lay it on her. Don't waste valuable time spending it with someone
who makes you uncomfortable. Life is too short.

tell her kindly your feelings. If she respects you ..... if not......

I sometimes work beside a die hard Atheist, his wife's a die hard Catholic they love each other but respect each others views and are completely open and honest about it.And that's how it, and you should be.

To start with, unfollow her or stop going to her FB page. Take a 1 or 2 day trip to see how it will work out.

Just level with her. Tell her that her extreme religiosity is making you feel very uncomfortable and that you do longer wish to go on the trip.

Without clarifying on the reason for uneasiness, it's hard to say. You know it better. You can ask yourselves some question like do I hate or like her company, do you fear she would reconvert you into the believers fold, or is it your insecurity with the believers.
My opinion is if you enjoy her company, if she never forces you to do the religious stuffs, you have no insecurities and of course if both of you care and respect each other, then there should not be any problem.

I would counter with "If you believe, God is with you always." while thinking to myself "Imaginary friends can always be with you"

I enjoy the company of people of all beliefs as long as they don't wave them in my face. Facebook isn't life, and I'd judge based on real life.

She may not be trying now to convert you but she will.....and if her actions already make you uncomfortable the feeling will be worse pretty soon.

I would tell her directly that you don't feel it's wise to share time together any longer.

Does she know you are an Atheist? If so unless she does this in person - I wouldn't sweat it.

My sister posts stuff like this - don't get me started - but knows how I'll react if she carries those dumb things back into reality.

We get along just fine. I don't try to convert her to Atheism - and vice versa.

If no money has been spent, I'd just tell her that you don't want to do it anymore. IDK what you're like, but my friends would accept that without question.

I think the important question is how strong is your connection? Is this just a polite acquaintance or is this someone whose company you really enjoy? If it's a solid friendship I wouldn't judge based on just posts, but if not you could always gracefully bow out with a reasonable excuse. Maybe visiting family instead, or reprioritizing your budget...something that won't make her feel rejected.

Talk to her.

If she's a good friend, and if you're going to be travel companions I assume she is, just bring it up in conversation and tell her your thoughts.

You know, if her religiosity bothers you I don’t think a trip would be wise. You will be somewhat closely confined. I would just be truthful. No one should be upset by that. Can they?

Communication is key. If you are hesitant to communicate your feelings on this to her, perhaps that's your answer. If she is familiar with your stance, have that conversation. Get ahead of it. Why dance around it? If either of you value the other for more than the other's religious position, then a conversation to clear the air shouldn't be an issue.

I'd be honest and tell her that her espousing of religion makes you uneasy. If she is worth your time she will accommodate. If she does, I would avoid the topic of religion in the future as she is too. Good luck, man. Best wishes.

If I were in your position, I would follow my feelings. I would cancel the trip and be completely open and honest about why. She has imaginary friends. She will be offended. There is no reason at all that you need to take that on yourself. It's hers. If she's offended because you are taking care of yourself, that's not your problem. C'mon, she's religious. She'll be offended by someone who doesn't believe as she does. And besides, why would you subject yourself to that experience?

Are you expected to pay for any part of her trip? If so then just say no. No sex, religious nonsense and paying is too much to ask for.

Tell her that you would lead her astray. That you don't want to get between her and God, for fear that you will be condemned to Hell. Also tell her you are doing it because you love her and want her to end up in Heaven, because it's all weed and orgies down there.

I have a similar issue with someone I knew many years ago. She wants to hang out and be buddies but you can't even have a conversation with her without her turning it into a psychology lesson on how to treat people. She's a LPC.

Are you offended by such posts? If not then proceed and expect more of the same.
If you are, then be honest and discuss your concerns. Why would you hide yourself from an old flame? Why would you suborn behavior you would probably not endure had you not already been "involved" with them? Either you have a relationship with openness and honesty or you do not. I am not sure why you even mentioned sex. btw, Dinosaurs are not involved in my reasoning.